The invention refers to a new apparatus for introducing water-soluble substances, especially plant treatment substances, such as fertilizers, plant protectives, weed killers and the like, into a water stream. The apparatus has a casing for carrying a water stream, which casing is provided with an inlet and an outlet for the water, and has a container for taking up said substances, which container is arranged within said casing for rotation around a rotational axis and has at least one opening.
In the field of gardening and in agriculture the problem frequently arises as to how best to apply a fertilizer to the soil or distribute a plant protective or a weed killer on a gardening or field area both from the point of view of incurring a minimum of work and from the point of view of saving costs. Especially with fertilizers, up to now it has been usual to distribute the generally granular or powder-like material in dry condition manually or by automatic distributing machines. This method has various serious disadvantages. As a result of the highly concentrated fertilizer in undissolved form burning is easily caused especially with young plants, the more so because the distribution is generally rather irregular and in places accumulation of fertilizer cannot be avoided. Furthermore, the fertilizer is partly lost as a result of wind or for other reasons or alternatively is distributed to the wrong areas so that an unnecessarily high consumption of fertilizer is incurred. Furthermore, the fertilizing effect is delayed, because a dissolving of the fertilizer by rain or pouring water is required before the fertilizer can be absorbed by the plants.
In order to avoid these disadvantages devices had already been proposed, by which fertilizers and other materials for treating plants are introduced into the pouring water.
In a known apparatus of this kind (British Pat. No. 8,912) the blending of the water with water soluble substances is obtained by a cylindrically shaped body, which is made from the material to be added to the water and which is arranged within a cylindrically shaped casing, with the water flowing through said casing in axial direction and thereby dissolving said body or material respectively. However, this known apparatus has the disadvantage that uniform dissolving of the material contained in the casing and a uniform blending of the water with this material is not possible. Furthermore, it cannot be avoided that undissolved or not completely dissolved material is added to the water flow, so that for example nozzles of a sprinkler connected with the outlet of this known apparatus are clogged after a short time. If a screen is provided at the output of the known apparatus, a clogging of the nozzles of a sprinkler can only be avoided, if the openings of this screen have a very small diameter. However, such a screen has the disadvantage, that the screen itself will be clogged by undissolved material, so that after a short time of operation the known apparatus will fail to work properly and no material or only an insufficient amount of said material will be mixed in with the pouring water. This is the more true as fertilizers rather often include materials, which ar-e difficult to dissolve in water.
Furthermore, devices for introducing water-soluble substances into a water stream are known (U.S. Pat. Nos. 1,679,561 and 2,610,090) in which devices a container is rotatably arranged within a casing, through which water flows. The container for taking up the water-soluble substances is provided with a number of openings in the peripheral wall, that means in a wall section, which is arranged concentrically with the axis of rotation. The principle mode of operation of all known devices is that the water-soluble material is mixed with the water inside the rotating container and the water blended with this material leaves the container through the openings provided in the peripheral wall. Also these known devices having a rotating container do not avoid the problem that undissolved material leaves the container together with the water through the openings, if these openings have a relatively large diameter. If the openings are of smaller diameter, they will be clogged after a short time of operation, so that no material or only an insufficient amount of material is mixed in with the water.